As is well known in the art, conventional inkjet printers generally employ one or more inkjet cartridges, often called “pens”, which eject drops of ink onto a page or sheet of print media. For instance, two earlier thermal ink ejection mechanisms are shown in U.S. Pat. Nos. 5,278,584 and 4,683,481, both assigned to Hewlett-Packard Company. Historically, the pens are usually mounted on a carriage, which is arranged to scan across a scan axis relative to a sheet of print media as the pens print a series of individual drops of ink on the print media. The series of drops collectively form a band or “swath” of an image, such as a picture, chart or text. Between scans, the print medium is advanced relative to the scan axis. In this manner, an image may be incrementally printed.
Over recent years the importance placed on the throughput of inkjet printers has risen dramatically. Throughput is generally measured as the number of pages of a given size, or the area of print media that a printer may ink in a given time.
One approach to increasing the throughput of such printers is to use one or more static arrays of print nozzles which span the width of pages to be printed on. Pages of print media may then be loaded onto a belt or a drum and transported under one or more page wide arrays of print nozzles, or print bars. Although such page wide array systems offer the possibility of increased throughput, they suffer from certain disadvantages.
In order to ensure satisfactory print quality, inkjet printheads must be periodically serviced. Conventional servicing operations include, for example, “spitting” and “wiping” routines. Spitting is the term given to the process by which a number of ink drops are fired through one or more nozzles of a printhead into a waste ink collection reservoir termed a spittoon. This process may be used in order to remove a blockage in the nozzle caused by dried ink or other matter. Wiping is the process by which the printhead surface is cleaned with a wiping element to remove any ink residue, paper dust, or other matter that has collected on the face of the printhead. Commonly, wiping is implemented using one or more elastomeric wiping elements which are loaded with an ink solvent such as polyethylene glycol (“PEG”) compound in order to facilitate the wiping process.
In scanning inkjet systems a “service station” mechanism is typically located within the printer chassis outside the media feed path. When a servicing routine is required, the inkjet printheads are moved to a position adjacent the service station so that the servicing may be carried out. However, the print bars of page wide printer systems are generally bulky. Thus, moving such print bars to a service station spaced apart from the media feed path tends to increase the working volume of the printer system and the complexity of servicing operations.
It would therefore be desirable to provide a printing device and method, which addresses the problems found in the prior art.